The present invention relates to a disk drive for reading and/or writing data from/on a disklike data storage medium such as an optical disc or a magnetic disk, which is stored in a cartridge type container.
Disklike data storage media are used extensively to store software or data for computer-related equipment, music, video and various other types of information thereon. Data may be read or written with a light beam or magnetism. Examples of data storage media using a light beam include CDs and DVDs. A floppy disk has been known as a data storage medium that used magnetism. Furthermore, some data storage media such as MOs and MDs use both a light beam and magnetism alike.
Among other things, a data storage medium of the type allowing the user to rewrite data is housed in a cartridge type storage case to protect the data stored there.
Japanese Patent Application Laid-Open Publication No. 9-153264 discloses such a cartridge type storage case (which will be referred to herein as a “disk cartridge”). As shown in FIG. 63, the disk cartridge 100 includes a cartridge body 101 to store a readable and/or rewritable disk 10. The cartridge body 101 has a window 101w on the upper and lower surfaces thereof so as to allow a drive mechanism (such as a spindle motor) for rotating the disk 10 and a read/write head to enter the cartridge body 101 and access the disk 10.
The disk cartridge 100 further includes a shutter 103 with a square bottom and a C-cross section in order to cover the window 101w on the upper and lower surfaces of the cartridge body 101 and to protect the side of the disk 10 exposed through the window 101w. 
As shown in FIG. 63, the shutter 103 is movable in the direction pointed by the arrow P. A spring (not shown) applies elastic force to the shutter 103 so as to make the shutter 103 shut the window 101w. Particularly when no external force is applied, the shutter 103 shuts the window 101w so as not to expose the disk 10.
In reading or writing data from/on the disk cartridge 100 using a disk drive (not shown), a shutter opener 104, provided for the disk drive, is used. Specifically, the protrusion 104a of the shutter opener 104 is fitted with a notched portion 103a of the shutter 103, and the disk cartridge 100 is pushed deeply into the disk drive in the direction pointed by the arrow Q. As a result, the shutter opener 104 turns around the center of rotation 104b in the direction pointed by the arrow R, thereby shifting the shutter 103 in the direction pointed by the arrow P. In this manner, the shutter 103 can be opened.
The shutter 103 of the disk cartridge 100 has a square bottom and a C-cross section as described above. However, it is usually difficult to make a shutter in such a shape. Also, to make the shutter slide smoothly, the shutter needs to be shaped with high precision. As a result, the cost of this part rises and eventually the cost of the disk cartridge 100 itself goes up, too.
Also, the shutter 103 with such a structure easily leaves a gap between the shutter 103 and the cartridge body 101 even while the window 101w on the upper and lower surfaces of the cartridge body 101 is closed. Thus, it is difficult to effectively prevent dust or dirt from entering the disk cartridge 100. Consequently, errors are more likely to happen while data is being read or written from/on the disk 10.
As a disk cartridge having a structure that can overcome these problems, Japanese Patent Application Laid-Open Publication No. 2002-50148 discloses a disk cartridge having a structure in which the window is opened or closed with a plurality of planar shutters. FIG. 64 is a perspective view of such a cartridge 200. FIG. 65 is an exploded perspective view illustrating the respective members of the cartridge 200.
The disk cartridge 200 includes a cartridge body 210 consisting of an upper shell 211 and a lower shell 212. The lower shell 212 has a window 212w on its lower surface so as to allow a drive mechanism (such as a spindle motor) for rotating the disk 10 and a read/write head to enter the cartridge body 210 and access the disk 10. On the outer surface of the lower shell 212, provided are positioning holes 215a and 215b for positioning the disk cartridge 200 on a plane parallel to the disk 10 within a disk drive (not shown) and a notch 212t for preventing the user from inserting the disk cartridge 200 upside down. On the inner surface of the lower shell 212, a first link spindle 212a and a second link spindle 212b are provided. As shown in FIG. 65, a window 212g for exposing a part of the outer periphery of a rotational member 230 (to be described later) is provided on a side surface of the lower shell 212. Two guide portions 212G and 212H are provided on both ends of the window 212g. 
In the cartridge body 210, provided are a shutter pair 220 for shutting the window 212w, a rotational member 230 that rotates around a point substantially matching the center of the disk 10, and a locking member 225. The shutter pair 220 consists of a first shutter 221 and a second shutter 222.
The rotational member 230 has a disk shape and also has a window 230w, which is positioned and shaped so as to completely match the window 212w when the shutter pair 220 is fully opened. Also, on the side surface of this rotational member 230, a first notched portion 231, a second notched portion 232 and a gear portion 233 located between the two notched portions 231 and 232 are provided so as to rotate and drive the rotational member 230 externally. On the lower surface of the rotational member 230 opposed to the shutter pair 220, rotation spindles 230a and 230b are provided for the first and second shutters 221 and 222, respectively.
The first shutter 221 has a rotation center hole 221a and a link groove 221b to which the rotation spindle 230a and the first link spindle 212a are respectively inserted, while the second shutter 222 has a rotation center hole 222a and a link groove 222b to which the rotation spindle 230b and the second link spindle 212b are respectively inserted. Thus, the first and second shutters 221 and 222 turn on the rotation spindles 230a and 230b, respectively.
The locking member 225 is supported in a rotatable position on a rotation shaft 212c provided for the lower shell 212. While the window 212w is closed, the convex portion 225a of the locking member 225 fits into the second notched portion 232 of the rotational member 230, thereby locking the rotational member 230 and keeping it from rotating.
In this disk cartridge 200, the upper shell 211 covers the entire upper surface of the disk 10, and therefore, a damper 240 is provided inside to clamp the disk 10 thereon.
Next, it will be described with reference to FIGS. 66 through 68 how the shutter pair 220 of the disk cartridge 200 carries out its opening/closing operation. FIGS. 66, 67 and 68 respectively illustrate a fully closed state, an opening state, and a fully opened state of the shutter pair 220.
As shown in FIG. 66, if the operating portion 225b of the locking member 225 is pressed in the direction pointed by the arrow P, then the locking member 225 turns on the rotation shaft 212c in the direction pointed by the arrow 225A. As a result, the convex portion 225a of the locking member 225 is disengaged from the second notched portion 232 of the rotational member 230, thereby getting the rotational member 230 ready to rotate. If the rotational member 230 is rotated in the direction pointed by the arrow S after having been unlocked with the operating portion 225b pressed, then the first and second rotation spindles 230a and 230b rotate in the directions pointed by the arrows T1 and U1, respectively. As a result, the rotation center holes 221a and 222a of the first and second shutters 221 and 222 also rotate in those directions. In addition, the link grooves 221b and 222b slide along the first and second link spindles 212a and 212b in the directions pointed by the arrows T2 and U2, respectively.
If the rotational member 230 is kept being rotated in the direction pointed by the arrow S, then the first and second shutters 221 and 222 move in the directions pointed by the arrows T2 and U2, respectively, while rotating around their rotation center holes 221a and 222a in the directions pointed by the arrows T1 and U1, respectively, as shown in FIG. 67. As a result, the shutter pair 220 is fully opened as shown in FIG. 68. Then, the window 212w of the lower shell 212 substantially matches the window 230w of the rotational member 230. Consequently, a drive mechanism (such as a spindle motor) for rotating and driving the disk 10 and a read/write head can now enter the cartridge body 210 and access the disk 10 stored in the disk cartridge 200.
The window 212w may be shut by performing the opposite of the opening operation described above, i.e., by rotating the rotational member 230 in the direction pointed by the arrow S′. As shown in FIG. 66, when the shutter pair 220 is closed to shut the window 212w fully, the locking member 225 is turned on its rotation shaft 212c in the direction pointed by the arrow 225A′ by the elastic portion 225c provided for the locking member 225 itself, thereby getting the convex portion 225a of the locking member 225 fitted with the second notched portion 232 of the rotational member 230 again. In this manner, the rotational member 230 is locked so as not to rotate and the shutter closing operation is finished.
As described above, since the link grooves 221b and 222b of the first and second shutters 221 and 222 are fitted with the first and second link spindles 212a and 212b of the lower shell 212, respectively, the rotational member 230 cannot rotate freely, but only to a predetermined degree, between the opened and closed states of the shutter pair 220. No matter to what degree the rotational member 230 has rotated with respect to the cartridge body 210, at least one of the first and second notched portions 231 and 232 and the gear portion 233 is exposed through the window 212g provided on the side surface of the cartridge body 210. For that reason, by rotating the rotational member 230 such that at least one of the first and second notched portions 231 and 232 and the gear portion 233 is engaged, the shutter pair 220 can be operated no matter in what state the shutter pair 220 is.
To stabilize the operation of the shutter pair in the disk cartridge 220, the disk cartridge needs to be held firmly. One of the easiest and safest ways to fill this need is to provide holding members 210a and 210b for the disk drive as shown in FIGS. 66 through 68 for the purpose of gripping the cartridge body 210 (of which only the lower shell 212 is shown in these drawings) on the side surfaces thereof.
As shown in FIGS. 69 and 70, Japanese Patent Application Laid-Open Publication No. 2002-50148 discloses a rack bar 250, including a first fitting convex portion 251, a gear portion 253 and a second fitting convex portion 252, which are arranged in line, as a means for rotating the rotational member 230. The first fitting convex portion 251, gear portion 253 and second fitting convex portion 252 respectively fit with a first notched portion 231, a gear portion 233 and a second notched portion 232 provided on the side surface of the rotational member 230. A side surface portion 231a with the first notched portion 231 is as high as the addendum plane of the gear portion 233. On the other hand, a side surface portion 232a with the second notched portion 232 is also as high as the addendum plane of the gear portion 233.
In opening or closing a shutter pair 220, the rack bar 250 is slid from the location shown in FIG. 69 to that shown in FIG. 70 in the direction pointed by the arrow 250A (i.e., substantially parallel to the side surface of the disk cartridge 200), thereby rotating the rotational member 230 as described above.
However, in order to slide such an integrally molded rack bar 250 along the side surface of the disk cartridge 200, a space needs to be provided near the side surface of the disk cartridge 200 to allow the rack bar 250 to shift with respect to the disk cartridge 200.
As a result, a holding member 210a for holding the disk cartridge 200 firmly interferes with the shifting space of the rack bar 250. Thus, if a sufficient space were allowed the rack bar 250 to shift freely, then the disk cartridge 200 could not be held firmly with the holding member 210a anymore, which is a problem.
Also, if the rack bar 250 is an integrally molded member, then the rack bar 250 and the rotational member 230 are interlocked together by utilizing the elasticity of the resin that makes the rack bar 250. Accordingly, the elasticity of the rack bar 250 may not be controllable appropriately. In that case, the rack bar 250 may not engage or disengage itself with/from the outer surface of the disk cartridge 200 smoothly enough. Or after having gone through a number of opening and closing operations, the rack bar 250 may be deformed plastically and may not be interlocked with the rotational member 230 perfectly anymore.